This invention relates to mobile air conditioning systems and more particularly to means for automatically controlling the air conditioning system of a vehicle for more economic operation.
Since the advent of vehicular air conditioning systems by far the majority have had compressors run directly off the engine, usually by a pulley and belt arrangement. Because the refrigerant compressors of air conditioning systems require a relatively large amount of power to properly function, propel power of the engine, particularly in automotive type applications, is reduced with a proportional increase in fuel consumption. In hard pulling situations such as traversing long, relatively steep grades, the added load of an air conditioning system can cause engine overheating and even dropping back to a lower gear.
Likewise, even on slight inclines greater additional loads are placed on the engine to move the thousands of pounds of vehicle weight up the same. At this point continued use of the air conditioning system requires greater fuel consumption than level or down hill conditions. Also, the majority of driving, except in mountainous areas, is up and down without extremely long grade climbs being necessary.
To overcome the problems enumerated above, various systems have been devised including manifold pressure control air conditioner power switches, complicated electronic speed detection and temperature sensing systems, as well as centrifugal switch controls. All of these systems, however, are either difficult to install, complex to maintain or are inadequate for the purposes intended.